Efficacy and safety of low-dose oral minoxidil in the management of androgenetic alopecia

INTRODUCTION

Treating alopecia can be challenging. The available treatments are topical minoxidil, low-dose oral minoxidil (LDOM), and 5-α reductase inhibitors like finasteride and dutasteride. Only topical minoxidil and finasteride 1 mg daily are FDA-approved, while the rest are used off-label. Recent research has suggested that oral minoxidil may be a safe and effective treatment for both female androgenetic alopecia (female AGA) and male androgenetic alopecia (male AGA).

AREAS COVERED

In this review, we explore the pharmacokinetics, mechanism of action, safety, and efficacy of oral minoxidil. Additionally, we discuss its effectiveness compared to other treatments available for female AGA and male AGA.

EXPERT OPINION

LDOM has demonstrated a favorable efficacy and safety profile in several trials. Subsequently, its use for the treatment of male AGA and female AGA is increasing. However, its use remains off-label, and through increased usage, we will get a better idea of the best dosage and monitoring guidelines. LDOM has also been used with some effectiveness in other forms of hair loss.

Treatment of Androgenetic Alopecia: Current Guidance and Unmet Needs

Androgenetic alopecia (AGA) is the most common cause of hair loss in men and women. Traditionally, topical minoxidil and oral finasteride have been the standard of care yielding mixed results. New treatments such as Low-Level Laser Therapy (LLLT), microneedling, platelet-rich plasma (PRP), and others have been extensively studied in the literature, and the purpose of this review is to provide a comprehensive discussion of the latest treatment methods and their efficacy in treating AGA. Novel therapies such as oral minoxidil, topical finasteride, topical spironolactone, botulinum toxin, and stem cell therapy offer interesting alternatives to standard of care therapies for patients. In this review, we present data from recent studies on the clinical efficacy of these treatments. Furthermore, as new treatments have emerged, clinicians have tested combination therapies to assess whether there may be a synergistic relationship between multiple modalities. While there has been a great increase in the treatments available for AGA, the quality of evidence varies greatly and there is still a great need for randomized double blinded clinical trials to adequately assess the clinical efficacy of some treatments. While PRP and LLLT have demonstrated encouraging results, standardized treatment protocols are needed to adequately inform clinicians on how to use such therapies. Given the abundance of new therapeutic options, clinicians and patients must weigh the benefits and risks of each treatment option for AGA.

Minoxidil: a comprehensive review

Topical minoxidil (5% foam, 5% solution, and 2% solution) is FDA-approved for androgenetic alopecia (AGA) in men and women.Mechanism of action: Minoxidil acts through multiple pathways (vasodilator, anti-inflammatory agent, inducer of the Wnt/β-catenin signaling pathway, an antiandrogen), and may also affect the length of the anagen and telogen phases.Pharmacokinetics: Approximately 1.4% of topical minoxidil is absorbed through the skin. Minoxidil is a prodrug that is metabolized by follicular sulfotransferase to minoxidil sulfate (active form). Those with higher sulfotransferase activity may respond better than patients with lower sulfotransferase activity.Clinical efficacy (topical minoxidil): In a five-year study, 2% minoxidil exhibited peak hair growth in males at year one with a decline in subsequent years. Topical minoxidil causes hair regrowth in both frontotemporal and vertex areas. The 5% solution and foam were not significantly different in efficacy from the 2% solution.Oral and Sublingual minoxidil (not FDA approved; off-label): After 6 months of administration, minoxidil 5 mg/day was significantly more effective than topical 5% and 2% in male AGA. Low-dose 0.5-5 mg/day may also be safe and effective for female pattern hair loss and chronic telogen effluvium. Sublingual minoxidil may be safe and effective in male and female pattern hair loss.

Safety of low-dose oral minoxidil for hair loss: A multicenter study of 1404 patients

BACKGROUND

The major concern regarding the use of low-dose oral minoxidil (LDOM) for the treatment of hair loss is the potential risk of systemic adverse effects.

OBJECTIVE

To describe the safety of LDOM for the treatment of hair loss in a large cohort of patients.

METHODS

Retrospective multicenter study of patients treated with LDOM for at least 3 months for any type of alopecia.

RESULTS

A total of 1404 patients (943 women [67.2%] and 461 men [32.8%]) with a mean age of 43 years (range 8-86) were included. The dose of LDOM was titrated in 1065 patients, allowing the analysis of 2469 different cases. The most frequent adverse effect was hypertrichosis (15.1%), which led to treatment withdrawal in 14 patients (0.5%). Systemic adverse effects included lightheadedness (1.7%), fluid retention (1.3%), tachycardia (0.9%), headache (0.4%), periorbital edema (0.3%), and insomnia (0.2%), leading to drug discontinuation in 29 patients (1.2%). No life-threatening adverse effects were observed.

LIMITATIONS

Retrospective design and lack of a control group.

CONCLUSION

LDOM has a good safety profile as a treatment for hair loss. Systemic adverse effects were infrequent and only 1.7% of patients discontinued treatment owing to adverse effects.

Effect of Oral Minoxidil for Alopecia: Systematic Review

Patients with major presentations of alopecia experience physically harmful effects and psychological comorbidities, such as depression and anxiety. Oral minoxidil (OM) has been suggested by dermatologists as a potential remedy; however, its effectiveness remains unclear. This systematic review aims to collate published studies and to analyze the effect of OM among patients diagnosed with any type of alopecia. For this systematic review, Medline/PubMed, Cochrane Central, EMBASE, Web of Sciences, and Latin American and Caribbean Health Sciences Information System were searched for relevant studies from inception to September 21, 2019. Of 1960 studies retrieved in several electronic databases and three additional records identified though reference list from potentially eligible studies, nine studies (one randomized controlled trial and eight nonrandomized controlled trials) met the requirements and were used in our analysis. Although we found positive effects in favor of OM, this should be interpreted cautiously due to very low quality of the evidence of outcomes in the selected studies. Definitive conclusions are not possible without high-quality trials. This review has highlighted the absence of high-quality randomized controlled trials evaluating OM in the treatment of various types of alopecia. Given the mild adverse events of OM, future studies should also analyze doses and duration to maximize efficacy and decrease side effects.

Oral minoxidil treatment for hair loss: A review of efficacy and safety

BACKGROUND

Although topical minoxidil is an effective treatment option for hair loss, many patients are poorly compliant because of the necessity to apply the medication twice a day, undesirable hair texture, and scalp irritation.

OBJECTIVE

In recent years, oral minoxidil at low dose has been proposed as a safe alternative. This study reviewed articles in which oral minoxidil was used to treat hair loss to determine its efficacy and safety as an alternative to topical minoxidil.

METHODS

PubMed searches were performed to identify articles discussing oral minoxidil as the primary form of treatment for hair loss published up to April 2020.

RESULTS

A total of 17 studies with 634 patients were found discussing the use of oral minoxidil as the primary treatment modality for hair loss. Androgenetic alopecia was the most studied condition, but other conditions included telogen effluvium, lichen planopilaris, loose anagen hair syndrome, monilethrix, alopecia areata, and permanent chemotherapy-induced alopecia.

LIMITATIONS

Larger randomized studies comparing the efficacy/safety of different doses with standardized objective measurements will be needed to clarify the best treatment protocol.

CONCLUSION

Oral minoxidil was found to be an effective and well-tolerated treatment alternative for healthy patients having difficulty with topical formulations.